A regular database or search application has primitive data types such as String (char, varchar, text …), Number (integer, long, float, double …), Date, Boolean. These don’t say anything about the data itself.
The NameAPI Index works with semantic data types, meaningful data types. These types represent concepts and describe the information. Examples are Surname (instead of String), Date of birth (instead of Date), gender (instead of Integer or String), IBAN (instead of String).
Fields can stand on their own, be part of an entity, or form an entity. A surname, first name and middle name can form a person’s name entity. An address entity can be made up of fields such as street name and house number, postal code and place name.